High strength concrete — Freeze/thaw testing and cracking

Abstract Cracks due to rapid freezing and thawing in water (ASTM C666 procedure A) of non-air entrained high strength concretes have been investigated using a procedure designed to avoid creating cracks during specimen preparation. Polished sections impregnated by immersing virgin water saturated slices in ethanol containing fluorescent dye (Fluorescent Liquid Replacement — FLR) were inspected in ultra violet light in an optical microscope. The fluorescent impregnated polished sections showed no cracking in any of the concretes before frost exposure, and extensive cracking after deterioration. The amount of cracks on the polished sections showed a good relationship to Durability Factors (DF) measured in the rapid freeze/thaw test. The crack volume calculated using a simple square grid model of cracks correlated reasonably to measured volume increase at frost testing.